Its an interesting article that goes over the fast pace the development into 3D printed guns is undergoing. My 2 cents, it would be a heck of alot easier and cheaper (most folks don’t have a 3D printer) to build a zip gun, or buy one. Still it is interesting tech, I would be interested to see it used for custom guns myself.
http://www.3ders.org/articles/20140922-the-evolution-of-3d-printed-firearms.html